A well known form of harvesting machine is a rotary combine. A typical combine includes crop harvesting apparatus which reaps grain stalks and other plant materials and feeds them to separating or threshing apparatus. The grain stalks or other crop and plant materials harvested in the field are moved rearwardly from a crop harvesting header assembly and introduced for threshing to the rotor assembly by a crop feeder assembly.
In a rotary combine, the rotor assembly includes a generally tubular rotor housing or cage mounted in the combine body. A rotatably driven rotor is coaxially mounted within the housing. The rotor comprises a front infeed or inlet section and a more rearward cylindrical threshing section, and is supported at opposite ends by front and rear bearing assemblies.
The cylindrical threshing section of the rotor and the rotor housing mount cooperating threshing elements which separate grain from other material in a threshing zone. The crop material is threshed as it spirals around the rotor threshing section and passes through openings in the rotor housing.
The ability to transfer crop materials from the feeder assembly to the threshing zone of the rotor assembly is a key to efficient combine operations. Many rotary combine rotors include an infeed or inlet section impeller comprised of a series of impeller blades or flights arranged at a forward end of the rotor. The impeller flights rotate within a transition region which is a part of the rotor housing. During harvesting operations, the generally linear movement of the crop materials received from the feeder assembly is converted by the rotor impeller flights in the transition region into a rotating, circulatory movement, in a rearward and radially outward direction. Reference in this regard, Tanis et al., U.S. Pat. No. 5,145,462 issued to Case Corporation.
If the infeed or inlet section of the rotor is operating inefficiently or poorly, power requirements of the rotor can be increased, the section can plug with crop materials, and components can suffer premature wear. Operational noise levels can also be heightened. Additionally, it has been found that it is desirable to have an air flow through the transition region from the feeder to the threshing apparatus, such that a large volume of airborne dust and other particulates do not exit the machine and impair the operator's view of the crop harvesting apparatus and operation thereof. An indication of poor airflow will typically be a dust cloud above and around the feeder.
Accordingly, what is sought is an improvement to threshing rotor inlet flights which facilitates crop material flow from a feeder to the threshing region, and which substantially reduces or eliminates outward air flow from the feeder and inlet region of the threshing apparatus.